Originally Posted by barnrat
You need to really sit hard in the saddle, you may be leaning to far forward and that is a que to the horse to speed up...
although the second part is true, I don't believe sitting hard/deep in the saddle will help. Try and imagine 'lifting' the horse with your seat and staying light. If you sit deep he your horse can interpret that as driving him forward.
Also, work with lots of circles and a lot of squeeze and release... make sure that there is a reward if he does slow down, even if it is just from a crazy trot to a semi crazy trot